MOLE - AMOUNT OF SUBSTANCE BASIC CHEMISTRY INFORMATION AND TUTORIALS

What is inside 1 mole?

Sometimes we need to keep track of the number atoms or molecules in a sample. We can’t go strictly by mass; different atoms and molecules have different masses.

One gram of water has over 2½ times as many molecules as one gram of ethanol because ethanol molecules are much more massive than those of water. It is not possible to count atoms and molecules because they are invisibly small and uncountably numerous.

To understand how chemists keep track of particles, it is helpful first to consider how builders keep track of nails.

A building project uses many more nails than anyone wants to count, so instead, nails are weighed. To plan a project, the builder consults a table that gives the weight of 1000 nails. For example, 1000 1½ inch tinned nails weighs 4 pounds. Based on this information, the builder knows how to count nails by weighing. It should be clear that this method will only work if all the nails are about the same mass.

To put this into a chemical perspective, a single one of these nails contains about 19,600,000,000,000,000,000,000 iron atoms. Clearly we can’t deal with atoms in thousands; the weight of a thousand atoms would not register on the most sensitive scale. The standard number of units—that is, atoms, molecules, or ions—used by chemists is 6.022 × 10^23, which is 6.022 multiplied by 1 followed by 23 zeros.

The reason for this clumsy-looking number is that it is about the number of atoms in one gram of hydrogen, the lightest of the atoms. An amount of stuff with this many particles is called a mole of the stuff. In chemical jargon, we say that the molar mass (also called atomic weight) of hydrogen atoms is one gram per mole.

The mass of a mole of something is called its molar mass or molecular weight (in the special case of the atoms of an element, it is sometimes called the atomic weight). The molar masses of atoms of the elements are determined by the numbers of protons and neutrons in the atoms.

Different elements have different molar masses, because their atoms weigh different amounts. The molar masses of the elements are listed on the periodic table.


Rather than think of H2O as a formula representing a single water molecule weighing 3.0 × 10-23 gram, we can think of it as representing a mole of water molecules weighing 18 grams. The formula tells us that each mole of water has two moles of hydrogen atoms (1 gram each) and one mole of oxygen atoms (16 grams each). We can think of chemical equations in terms of moles. The equation H2 + ½O2 → H2O makes sense if we read it as one mole of H2 reacts with half a mole of O2 and yields one mole of H2O.

CALORIES, GLUTEN, AND CARBOHYDRATES IN BEER BASIC INFORMATION AND TUTORIALS

How much calories, gluten, and carbohydrates are there in beer?

Calories in Beer
There is a perception that beer is very fattening. To address this, we need to talk about the primary function of food. Living cells combine food with oxygen to give carbon dioxide, water, and energy for life functions.

The overall chemical reaction is the same as burning the food in air, but under controlled conditions and at lower temperature. Extra food that is not needed for the cell’s energy requirement is converted to long-term energy storage compounds, including fat.

The energy potential in food is determined by burning the food and measuring the amount of heat released. Food energy is usually measured in Calories (1 Calorie = 1000 calories = 4184 joules = 4 BTU). Most people need roughly 2000 Calories a day depending on their size and level of activity.

The Food Energy Potential table tells us that the fattening aspect of beer is primarily from the foods that tend to go with it. Two beers, a half dozen wings, and a slice of pizza come to a shocking 1816 Calories. Two beers and a bunch of carrot and celery sticks would come to less than 400 Calories.

Gluten in Beer
Gluten is a mixture of proteins found in the seeds of certain grassy plants, particularly wheat, barley, and rye. The gluten proteins fall into two classes based on solubility: glutelins and prolamines. Wheat has a prolamine called gliadin, barley has hordein, and rye has secalin.

The nutritional issue with gluten is an immune disorder called celiac disease, which affects as much as 1% of the population. Persons with celiac disease react to certain portions of prolamine molecules with a cascade of molecular events leading to damage to the lining of the small intestine.

The condition is life threatening and is treated with a diet that excludes all gluten. In addition to persons with celiac disease, many others believe that there is a health benefit to excluding or limiting the intake of gluten. This leads to two questions. Is beer safe for persons with celiac disease? Is beer low enough in gluten to be suitable for persons seeking to limit their gluten intake?

Barley beer has been found to contain traces of hordein fragments of a type associated with celiac symptoms. There is no established safe level of gluten intake for persons with celiac disease. This gives a tentative answer to the first question: no, beer is not known to be safe for persons with celiac disease.

Gluten-free beer made without wheat, barley, or rye has been found to be free of traces of celiac-related protein fragments. As for the second question, the brewing process removes more than 99% of the gluten from the barley used to make the beer. Moderate consumption of beer could be regarded as consistent with a low-gluten diet.

Carbohydrates in Beer
Some low-carbohydrate diet books make the incorrect assumption that beer has a high concentration of maltose, a simple carbohydrate that these diets seek to avoid. In fact, the yeast consumes all the maltose and other simple sugars during fermentation.

The typical non-light 12 ounce (355 milliliter) beer contains about 12 grams (0.42 ounce) of carbohydrates, a light beer would contain about half of that. In either case, the carbohydrates would be complex, with only traces of simple sugars.